The present invention relates to a vehicle lamp and a method for indicating the vehicle lamp. Particularly to a vehicle lamp provided with a plurality of LEDs or a combination of at least one LED for emitting short-wave light and a fluorescent material. The vehicle lamp can be adapted particularly to a rear combination lamp of a vehicle.
In a rear combination lamp disposed in a rear portion of a vehicle, bulbs are generally used as light sources. The rear combination lamp has a tail stop lamp portion, a turn lamp portion, and a back lamp portion. Light emitted from the bulbs is radiated out through lenses (filters) disposed in these portions and decorated with indication colors respectively. The following problems arise from the use of such bulbs as light sources. Firstly, much electric power is consumed. Secondly, the life of each bulb is so short that the bulb must be frequently exchanged for a new one. Thirdly, each of indication portions such as a tail stop lamp portion needs a color filter (color-decorated lens). Therefore, a rear combination lamp has been proposed as a system using LEDs as light sources instead of the bulbs. For example, there has been proposed a stop lamp using LEDs as its light sources to thereby perform stop lamp indication on the basis of the color of light emitted from the LEDs per se (Japanese Patent Publication No. JP-11-96808A). By the use of such LEDs, the problems peculiar to the bulbs can be solved. When such an LED light source is used, a plurality of LEDs are required and disposed, for example, in the form of a matrix so that the plurality of LEDs can cover the whole surface of a lens because there is the existing situation that equal luminance to that obtained by one bulb cannot be obtained by one LED.
Meanwhile, stop lamps of a vehicle are provided to signify deceleration or stop to a vehicle in the rear, and required to have high visibility in terms of safety. The visibility is, however, lowered in a bad condition for field of view, for example, in the case where fog is generated in the night. Moreover, when a driver who is driving a vehicle does not focus on a rear portion of a vehicle in the front, for example, in the case where the driver shifts the eye view toward another direction from the traveling direction of the vehicle, the visibility of stop lamps of the vehicle in the front is lowered. As described above, there is still room for improvement in the related-art stop lamp indication using a single color of red because it can be hardly said that the visibility in the stop lamp indication is sufficient for various running situations.
Moreover, when LEDs are used in a vehicle rear lamp in the above manner, there has been a problem that design characteristic becomes poor because light emitted in the form of points on a surface of a lens is observed and the light on the whole surface cannot be made uniform in luminance due to the luminance difference between the LEDs.